Optimization of dynamic nuclear polarization signals for high sensitivity NMR and MRI of cancer metabolism

Dissolution dynamic nuclear polarization (DNP) is a physics-based technology that can amplify liquid-state nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) signals by >10,000 times. In DNP, a sample containing the target nuclei (e.g. carbon-13, nitrogen-15) and trace amount of free radicals (e.g. trityl OX063, TEMPO) dissolved in a glassing matrix is subjected to low temperature and high magnetic field, then irradiated with microwaves close to the electron paramagnetic resonance (EPR) frequency of the polarizing agent. This process transfers the high degree of electron spin alignment to the nuclear spins, resulting in high nuclear polarization, thus stronger NMR signal. Once hyperpolarized, the frozen saple is rapidly dissolved by superheated water or other solvents resulting in hyperpolarized liquid at room temperature that retained most of the enhanced NMR signal at cryogenic temperature. In this presentation, optimization steps of the DNP technology will be discussed as well as its applications in biomedical NMR and MRI of the aberrant biochemistry in cancer.